Stringed musical instrument



April 20, 1943.

J. W. MGBRIDE STRINGED MUSICAL INSTRUMENT Filed Sept. l5, 1941 3Sheets-Sheet l A muunni April 20, 1943- J. w. MCBRlDE 2,316,800

STRINGED MUS ICAL INSTRUMENT Filed Sept, `l5, 1941 3 Sheets-Sheet 2 7Xdo n. M65/7b? @Wmv ATTORNEY April 2o, 1943. J. w. vmamma v.2,316,800

STRINGED MUSICAL INSTRUMENT Filed Sept. l5, 1941 3 Sheets-Sheet 3INVENTOR ./an iff/Vc fy'a ATTORNEY Patented Apr. 20, 1943 UNITED 'STATESPATENT OFFICE Claims.

This invention relates to a stringed musical instrument, and moreparticularly to an instrument in which the pitch of the musical soundcaused by vibration of any of the strings is capable of being determinedby determining the free length of vibration of the string. This processis accomplished usually by stopping the string against a surface by thenger of the player.

This application is a continuation in part of an application filed inthe name of John W. McBride on April 14, 1941, bearing Serial No.388,379, and entitled Stringed musical instrument.

Such stopping is commonly employed in playing such instruments as aguitar or violin, in

I which the neck oi the instrument forms a convenient surface againstwhich the string being played can be pressed by the linger,

In view of the fact that the fingers may be required to be piaced overthe strings at any point along the strings, prociency in playing such aninstrument is dependent upon manual and digital dexterity.

It is one of the objects of this invention to make it possible tocontrol or adjust the free length of the vibrating string in a moreconvenient manner, and without the necessity of materially shifting theposition of the hand.

In order to accomplish these results, use is made of an elongated rodarranged beneath the string to be controlled, and extending generally inthe direction of the string. The rod has a series of longitudinallyspaced teeth, formed by an interrupted crest that progresses angularlyabout the longitudinal axis of the rod, in a helical-like manner. Byadjustment of the rod about a longitudinal axis, the string is caused torest upon any desired tooth or point of the interrupted crest, and itsfree length of vibration is thus determined. The rotation of this rod tocause the teeth or crest to assume the desired positions is accomplishedby depressing linger keys. Accordingly, it is another object of thisinvention to provide a mechanism under the control of the ngers of theplayer, for rotation of a string stopping bar or rod of this character.

The invention possesses many other advantages, and has other objectswhich may be made more easily apparent from a consideration of a fewembodiments of the invention. For this purpose there are shown severalforms in the drawings accompanying and forming part of the presentspecification. These forms will now be described in detail, illustratingthe general principles of the invention; but it is to be understood thatthis detailed description is not to be taken in a limiting sense, sincethe scope of this invention is best dened by the appended claims.

Referring to the drawings:

Figure 1 is a plan view of a musical instrument incorporating theinvention;

Fig. 2 is an enlarged part sectional view, taken along plane 2-2 of Fig.1, a part of the instrument being omitted to reduce the size of theiigure;

Figs. 3, 4 and 5, are sectional views on a further enlarged scale, takenalong. correspondingly numbered planes of Fig. 2;

Figs. 6 and 7 are sectional views as seen on correspondingly numberedplanes of Fig. 4;

Fig, 8 is a pictorial View of a finger key adapted to be used in theinstrument incorporating the invention;

Fig. 9 is a pictorial View of one of the elements utilized in connectionwith the keys;

Fig. 10 is a fragmentary detail elevation of one form of rod used fordetermining the free length of a vibrating string;

Fig. 11 is a cross sectional view on an enlarged scale as seen on planelI-II of Fig. 10;

Figs. 12 and 13 are views similar to Fig. 10, showing modiiied forms ofrods; and

Fig. 14 is a detail cross section as seen on plane |4-I4 of Fig. 14. Inthe present instance, the invention is shown as incorporated in aguitar, although it s capable of being utilized with many types ofstringed musical instrument. Instead of utilizing a hollow resonantbody, to set up or augment the sound vibrations, the instrument is shownas capable of being connected with appropriate electrical amplifyingapparatus. For this purpose the body I (Figs. 1 and 2) of the guitar isshown as made of solid wood or other appropriate material. Extendingfrom the-body l is the elongated neck portion 2. This neck portionterminates in the flat peg board 3. In the present instance, a fourstring guitar is illustrated, the four strings being designatedrespectively by the reference characters 4, 5, 6 and l.

For maintaining these strings under tension, a bridge member 8 (Fig. 2)may be appropriately supported adjacent the end of the body portion l.This bridge is located in the recess 3l formed in the top of body I.This bridge member 8 is provided with a series of apertures 9, and eachaperture may be provided with a rearwardly extending enlarged portionI0. These apertures 9 serve as anchoring apertures for the strings.

Each of the strings for example may be provided with an enlarged ballend The strings may be passed through the respective apertures 9, theball being accommodated in the enlarged portion l5. The ball beinglarger than the aperture 9, it engages the edge of the aperture 5, thetension on the strings may be exerted.

The board 3 may be provided with the posts or pegs l2, I3, l and I5,serving as anchors for the free ends of the strings. These posts may bearranged to be rotated as desired by the thumb pieces i5, to wind thestrings upon the posts.

The strings are stretched under tension so that they are in Contact withtwo separated points. The pitch of the note caused by free vibrationbetween these points is a function of the mass per unit length of thestring, 'and the tension. Shortening of the free vibrating length of thestring causes an increase in pitch. All this is well understood. Thebridge 5 has an upper surface upon which the right hand ends of thestrings rest. Therefore the edge of this bridge S forms one of thestationary points.

The peg board 3 forms an abrupt shoulder I9 (Fig. 6) with the neck 2. Atthis portion of the neck 2, there is a metal bracket having a verticalwall I3 which is disposed against the shoulder i9. This bracket isappropriately fastened to the top surface of the neck 2. The verticalWall |8 is provided at its upper edge with a series of slots 2li (Figs.4 and 6). The strings slope downwardly along board 3. They contact thebottom surfaces of these slots. As will be described hereinafter, thefree or open position of the strings is determined not by the slots 2U,but by a device hereinafter to be described, and operating to form stopsfor the strings at some point to the right of bracket I1.

As in the usual guitar, the neck member 2 may be provided with a plate2| carrying the graduated marks i2 and underlying the strings 4, 5, 6and l. Its left hand edge as shown most clearly in Figs. 3, 5 and 6, mayabut the right hand edge of the bracket l'i.

As most 'clearly illustrated in Fig. 2, the bridge 8 may be concealedbeneath a sheet metal cover member 22. This cover member 22 is shown ashaving a depending wall 23 extending downward over the edge of the bodyl. Conveniently this right hand edge of the body may be provided with arecess so as to permit the depending member 25 to lie flush with thebody i. This cover member 22 may be secured as by the aid of the screws24.

At its front edge the cover member 22 may be provided with a steppedportion 25 connected as by the sloping connection 25 with the main partof the cover member. This portion 25 is disposed so as to be flush withthe top surface of body i. Through connection 25 there are clearanceapertures 27 to permit free passage of the strings. An anchor for thisend of the cover piece 22 may be provided by the aid of a strap 28fastened to the lower side of extension 25 and having a slot 29 therein.This slotted end is intended to be passed underneath the head of a screwSi) located in the bottom of the cut-out space 3|.

The vibrations of the strings li, 5, 6 and are intended to aiect anelectro-magnetic pickup device indicated diagrammatically by thereference character 32. The strings are shown in this instance aspassing directly above th'e pickup device 32. Leads from this device mayextend through aperture 0| (Fig. l) to the exterior of the instrument.

In the conventional playing of a guitar, the fingers of the left handare used to stop the strings 4, 5, 6 and 'I against the neck. Inaccordance with the present invention, the ngers are utilized to depressthe closely spaced finger buttons or keys 33, 3d, 35 and 36 (Figs. l, 5and 8), located near the end of the neck. Thus the hand does not have tobe movedl from the end position, and accordingly extreme manualdexterity is no longer essential.

The manner in which these buttons control the free length of the stringswill now be described in connection with the string 5 (Fig. 6). Themechanisms for the other strings are quite similar and will be describedonly insofar as they may differ in detail from the mechanism associatedwith string 5.

Located beneath the string 5 is a rotatable rod 3l (Figs. 2, 3, 4, 5 and5). Its axis of rotation is substantially parallel to the string. At itsright hand end this rod is provided with a stub shaft portion 35journaled in a bracket 39 (Fig. 2). This bracket 59 overli'es thevertical wall (i0 formed in the body member and located at the righthand end of the hollowed-out portion 4| of the body i. VThe left handportion of rod 37 carries the extension 42 (Figs. 5 and 6) that isjournaled in the vertical wall |8 of the bracket i'i. This rod Si, asshown most clearly in Figs. 10 and il, is provided with a series ofteeth |22 formed by the interrupted crest Yof a helical-like ridge s3.This ridge G3 progresses angularly along the longitudinal axis of therod 37.

As clearly shown in Fig. 1l, this ridge 43 is not high enough to contactthe string with which the interrupted crest is intended to cooperate.The teeth or crests |22 however are high enough so that they willcontact successively the bottom surface of string 5 as the rod is turnedabout its axis. The longitudinal spacing of teeth |22 agrees with thespacing of the frets or graduations |2|, on the finger board 2 i, asshown in Fig. 1. Thus, as the rod 3i is turned clockwise as viewed inFig. 3, successive teeth |22 will engage string 5 and progressivelyshorten its eiective length. By referring to Fig. l1 it will be notedthat teeth |22 are separated by equal angular distances, accordingly thepitch angle of ridge 43 and the teeth thereon increases toward the rightas the length of the string 5 is shortened. Thus equal angular movementsof rod 31 and hence equal movements of operating key 35 are effective atany point of the scale to tune the string to successive notes. This hassome advantages in promoting ease of playing. Furthermore, each tooth|22 has an angular extent slightly greater than the angular separationof the teeth, so that successive teeth overlay by a small amount. Inthis way, the string is never released between engagement by successiveteeth, andthere is no possibility of an annoying uping caused bythefaces of the teeth engaging thestring.

With the teeth |22 disposed in planes normal to the axis of rotation asin the form of Fig. 10, the pitch of the note emitted by the string isnot dependent on the exact angular position of the particular toothengaging the string. Itis obvious that the eiective length of the stringand hence the Vnote will be the same regardless of whether the center orone or the other edgeV portions of the tooth engages the string.

It may be desirable lto make it possible to vary the pitch of the noteslightly by a small movement of the operating key. This may be readilyaccomplished by inclining the teeth with respect to the correspondingplane of rotation. Such an arrangement is shown in Fig. 12. Therein arod |24 substantially the same as rod 31 is provided with teeth |25arranged on a helicallike ridge |26 as before. These teeth |25 areinclined with respect to their planes oi rotation and may beequiangularly spaced and arranged to overlap slightly.

. It will be apparent that the eiective length of the string will dependon what point of the particular toothengaging the string is contacted,whether near the center or adjacent one end or the other.

In Figs. 13 and 14, a rod |21, similar to rod 31 is shown, but on whichthe ridge |23 is a true helix. Thus the teeth |29 thereon are separatedby angular distances which vary with the longitudinal spacing of theteeth. The angular extent of the teeth |29 varies in accordance withthis angular spacing, so that successive teeth overlap slightly asbefore. With the teeth arranged in this manner, the angular movement ofthe rod, as well as the movement of the corresponding operating keybecomes progressively less as the pitch becomes higher in a manneranalogous with the closer spacing of the frets. Thus, for successivelyhigher notes, the amount of movement of the key 35 as it rotates the rodto tune the string becomes less and less, as will be apparent from thefollowing description of the key mechanism.

The finger key 35 is associated with the rod 31 so that pressure exertedon this key inwardly, as by one of the lingers of the left hand of theplayer, will cause the rod to be rotated. The extent of the depressionof the key in the direction transverse to the neck 2 determines theangular position of the rod 31, and the corresponding position of thepoint along the ridge 43 which is in contact with string 5.

Key 35 is shown to best advantage in Figs. 5, 6 and 8. It is guided formovement transverse of the instrument in a manner now to be described.Thus the key 35 has a lower portion 44. The lower surface of thisportion 44 rests upon the bottom of a square-cut slot 45 in the bracket|1. This slot 45 is undercut at the ieit hand edge, there being anoverhanging iiange 46 as shown most clearly in Fig. 6. The lower portion44 is provided with the projecting side flanges 41 and 48. The left handange 48 is accommodated beneath the projecting edge 46. The right handiange 41 is overlaid by a detachable stop piece 45. This piece is shownto best advantage in Fig. 9. It is screwed to the bottom of the bracket|1 as by the aid oi screws accommodated in the apertures By this meansthe key 35 is guided for transverse movement. A rack 5| is arranged onportion 44. This rack is adapted to engage the pinion 52 mounted on therod 31.

V As shown most clearly in Figs. 5 and 6, this pinion 52 is attached tothe reduced portion 42 of the rod 31 and abuts a shoulder formed betweenthis reduced portion 42 and an enlarged portion 53. The rod 31 isconstantly urged and in a resilient manner in a counterclockwisedirection by the aid of a helical spring 54 disposed over the extension42. The right hand end oi this spring is anchored in a collar 55 thatabuts the pinion 52. It is provided with a set screw 56 whereby theangular position of the collar 55 may be adjusted. At the leit'hand endof the extension 42 there is a collar 51 which is free to rotate on theextension 42 and to which is anchored the left hand end of the spring54. This collar is arranged to be angularly adjustable within the sleeve53 shown as formed integral with the wall |8 of bracket |1. The collar51 may be maintained in adjusted position as by the aid of the set screw59.

Thus in order to adjust the tension of the spring 54, either one or bothof the collars 55 or 51 may be appropriately rotated and maintained inadjusted position.

The constant force urging the shaft 42 and rod 31 in a counterclockwisedirection causes the key 35 to be urged upwardly as viewed in Fig. 5. Astop is provided to limit this upward movement at the point where therod 31 assumes the position of Fig. 5. For this purpose the plate 49(Fig. 9) is utilized. This plate 49 has the projecting edges 69 and 6|.The projecting edge 69 is arranged to overlie the iiange 41. As shownmost clearly in Fig. 8, the flange 41 is cut back at the iinger engagingend of the button 35 to accommodate the extension 65. In this way ashoulder 62 is formed on the key 35 which is urged against the extension60 when the key 35 is released.

The ,other keys 33, 34 and 35 similarly control the positions of bars53, 64 and 55. The axes of all of the bars are parallel; `and all of thekeys 33, 34, 35 and 35 are placed compactly adjacent @the end of theneck portion 2. In this way the fingers or the left hand may be readilyutilized without movement of the hand as a whole along the neck of theinstrument.

Thus for example the rod B5 controlling the free length of string 4carries the pinion 66 (Figs. 5 and 6). This pinion 66 is displaced in anaxial direction from the pinion 52, but in other respects the mechanismis entirely similar to that already described. The extension 6| of stopplate 49 operates against the corresponding abutment on the lowerportion of key 35. The torsion spring |02 in this case is somewhatlonger than the spring 54.

Similarly the button 34 operates the rod 64. In this case the pinion 61is spaced tow-ard the left of fthe pinion 52. Accordingly, torsionspring |03 is somewhat shorter than spring 54.

The button 33 controlling the position of the rod 63 serves to rotatethe pinion 68. In this case the pinion 68, as shown most clearly inFigs. 5 and 6, is arranged adjacent the left hand extremity of thereduced extension 59. An intermediate bearing standard 10 is providedfor this extension 59. Within the bearing standard is the angularlyadjustable collar 1l. The torsion spring 12 has its left hand endanchored to the collar 1| (Fig. 7). Its right hand end is anchored tothe angularly adjustable collar 13 placed at the right hand end of theextension 69. Furthermore, in order to provide stops against upwardmovement oi the keys 33 and 34 as viewed in Fig. 5, stop member 14 (ofthe same structure as stop 49) is utilized.

The rack and pinion mechanisms are provided with a cover member 15(Figs. 1, 2, 3, 4, 6 and 7.) This cover member as shown most clearly inFigs. 4 and 6, has a notched flange 15 overlying the top edge of walli8. At the opposite edge it has a flange 11 disposed slightly to theleft of the left hand edges of the bars 31, 63, 64 and B5. Furthermore,the cover 15 has an end wall 18 (Fig. 5) having depending flanges 19 and80,

which are continuations respectively of the flanges 'i6 and 17. Theseanges 'I9 and '80 serve to support the cover 15 in a pivotal manner.rIhus the flange 79 (Fig. 5) carries the pin shaft 8l engaging in anapertured ear 82 formed as an extension of the wall I3. The oppositeflange 80 is arranged to overlie the threaded ear Y83. This threaded earis engaged by the screw 84 that serves as a pivot shaft for flange 8U.The cover 75 may thus be swung up on these supports, to expose theringer key mechanism and to permit adjustments to be made.

As shown most clearly in Figs. '4, 6 'and '8, the top portion 85 of eachof the nger keys or Vbuttons 33, 34, 35 and 36 is arranged to telescopeunderneath the cover 15. This top portion may be provided with a seriesof marks 8&5 to serve las a guide for the player in determining how farthe buttons must be pressed inwardly to secure a definite pitch. Thesemarks are adapted to cooperate with the open edge 8l (Fig. el) at theright hand side of the cover I5. The cover T5 may also be provided withspring vlingers 88 located between the finger keys 33, 311, 35, S5, andadapted to snap over corresponding spring finger extensions 89 formedintegrally with the bracket I1. These spring fingers serve detachably tore strain movement of cover 'i5 about the axis of pin 8| and screw Sli.

Control of the volume of the impulses transmitted through the pickupmechanism 32 is conveniently accomplished by the aid of a Variableresistance 9i embodied in the neck 2 of the instrument. Thus leads '96(Figsf2 and 3) extend from device 32 through an elongated aperture 92 inthe instrument which leads to the chamber 93, in which is mounted theresistance '9 t.

The variable resistance 9i is controlled optionally by lever S5 or 95,depending on whether the instrument is slung from the players neck andsupported by the aid of the left hand or whether the instrument isresting on the players lap.

The guitar, as suggested hereinabove, may be supported as by the aid ofa sling hung around the neck. In this event the sling may be Vanchoredto a button Iii arranged at the yend of the body Alternatively, it maybe supported in the lap of the player.

To guard against possibility of any of the strings 4, 5, 6 or 'irattling in their respective supporting notches 253, a damping member|30 is provided to engage the strings. As clearly shown in Figs. 6 and'7, a light metal channel iti extending across the cover i5 is mountedon the under side of the cover, and a rubber strip i3d is cementedtherein. The parts are so arranged that this strip exerts a slightdownward pressure against each of strings 4, 5, 5 and 1.

What is claimed is:

l. In a stringed musical instrument, means for tensioning a stringbetween two i'lxed points, and means for adjusting the free length ofthe string, comprising a rotatable rod having means forming a pluralityof axially as well las -angularly spaced teeth for successively engagingthe string.

2. In a stringed musical instrument, means for tensioning a stringbetween two xed points, and means for adjusting the free length of thestring, comprising a rotatable rod havingV means forming a plurality ofteeth for successively engaging the string, said teeth being disposed ina helical-like row on the rod.

3. In a stringed musical instrument, means for tensioning a stringbetween two xed points, Vand means for adjusting the free length of thelstring in definite steps in accordance with va musical scale,comprising a rotatable rod with a 'plurality of teeth thereon, forengaging the string, 'Said teeth being arranged in helical-likeformation, and means for lrotating the rod.

4. In a stringed musical instrument, means fo'r tensioning a stringbetween two iixed points, and means vfor adjusting the free length ofthe string in definite steps in accordance with a musical scale,comprising a rotatable rod with a plurality of teeth thereon, forengaging the string, said teeth being arranged in helical-likeformation, the pitch angle of said helix varying progressively, wherebya constant increment `of angular mbation of the rod serves to tune thestring for successive notes of said scale.

5. In a stringed musical instrument, means for tensioning a stringbetween two fixed points, and means for adjusting the free length of thestring in denite steps in accordance with a musical scale, comprising arotatable rod with a plurality of teeth theeon, for engaging the string,said teeth being arranged in helical-like formation, the pitch angle ofsaid helix being constant, whereby the amount of angular movementimparted to the rod to tune the string to successive notes of said scalevaries with the pitch of the note.

6. In a stringed musical instrument, means for tensioning a stringbetween two xed points, means for adjusting the free length of thestring in steps in accordance with a musical scale, said meanscomprising a rotatable rod having teeth thereon for successivelyengaging the string, said teeth being inclined with respect to a planenora mal to the axis of the bar, whereby angular movement oi the baralters the free length 'o'fthe string so that the string may be tuned inlex'- act accord with said scale.

'7. A bar for use in tuning a tensioned string comprising a helical-likecrest so disposed as to clear the string and teeth arranged along thecrest and extending transversely thereof for engaging the string.

8. A bar for use in tuning a tensioned 'string comprising a helical-likecrest so disposed as to clear the string and teeth arranged along thecrest and extending transversely thereof for en-Y gaging the string,said teeth being axially spaced in accordance with a musical scale.

9. In a stringed musical instrument, means *forl tensioning a lstringbetween two fixed points, means for adjusting the free length oi the'string comprising a rotatable bar having an interrupted crest extendingtransversely of the axis of the bar, and means for rotating the bar tobring a desired portion of the crest into engagement with the string,said crest at the point of engagement dening one limit for the said freelength.

10. In a stringed musical instrument, means for tensioning a stringbetween two iixed points, means for adjusting the free length vof thestring comprising a rotatable bar having an interrupted crest extendingtransversely of the axis of the bar, and means for rotating the bar tobring a desired portion of the crest into engagement with the string,said means comprising a pinion secured to the bar, a rack slidablysupported for cooperation with the pinion, a nger key adapted to urgethe rack in one direction, and means resiliently opposing such movementof thejrack.

JOHN W. MCBRIDE.

